When we think of animals and plants, we have a pretty good way of dividing them into two distinct groups: one converts sunlight into energy and the other has to eat food to make its energy. Well, those dividing lines come crashing down with the discovery of a sea slug (海蛞蝓) that's truly half animal and half plant. It's pretty incredible how it has managed to hijack the genes of the algae (藻类) on which it feeds.
The slugs can manufacture chlorophyll, the green pigment (色素) in plants that captures energy from sunlight, and hold these genes within their body. The term kleptoplasty is used to describe the practice of using hijacked genes to create nutrients from sunlight. And so far, this green sea slug is the only known animal that can be truly considered solar-powered, although some animals do exhibit some plant-like behaviors. Many scientists have studied the green sea slugs to confirm that they are actually able to create energy from sunlight.
In fact, the slugs use the genetic material so well that they pass it on to their future generations. Their babies retain the ability to produce their own chlorophyll, though they can't generate energy from sunlight until they've eaten enough algae to steal the necessary genes, which they can't yet produce on their own.
"There's no way on earth that genes from an alga should work inside an animal cell," says Sidney Pierce from the University of South Florida. "And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they have a way of not starving to death until they find more algae to eat."
The sea slugs are so good at gathering energy from the sun that they can live up to nine months without having to eat any food. They get all their nutritional needs met by the genes that they've hijacked from the algae.
正确答案及解析
正确答案
DADCB
解析
当我们想到动物和植物时，我们有一个很好的方法将它们分为两组：一组将阳光转化为能量，另一组必须吃食物来制造能量。好吧，随着真正半动物半植物的海蛞蝓的发现，这些分界线崩溃了。它如何成功劫持了它赖以生存的藻类的基因，这真是令人难以置信。
蛞蝓可以制造叶绿素，植物中的绿色色素，从阳光中获取能量，并将这些基因保存在体内。这个术语被用来描述利用被劫持的基因从阳光中创造营养的做法。到目前为止，这种绿色的海蛞蝓是唯一被认为是太阳能的动物，尽管有些动物确实表现出一些类似植物的行为。许多科学家研究了绿海蛞蝓，以证实它们实际上能够从阳光中产生能量。
事实上，鼻涕虫对遗传物质的利用如此之好，以至于它们会将其遗传给后代。它们的宝宝保留了自己产生叶绿素的能力，尽管它们不能从阳光中产生能量，除非它们吃了足够的藻类来窃取必要的基因，而这些基因他们自己还不能产生。
来自南佛罗里达州大学的Sidney Pierce说：“地球上的藻类不可能在动物细胞内起作用。”然而，在这里，他们做到了。它们让动物依靠阳光来获取营养。因此，如果它们的食物来源出了问题，它们就有办法不饿死，直到找到更多的藻类来吃。”
海蛞蝓非常善于从太阳收集能量，它们可以活到九个月而不必吃任何食物。它们从藻类中获取的基因满足了它们所有的营养需求。
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